package com.leve.admin.common;

import java.security.MessageDigest;

public class CheckSumBuilder
{
  public static String getCheckSum(String appSecret, String nonce, String curTime)
  {
    return encode("sha1", appSecret + nonce + curTime);
  }

  public static String getMD5(String requestBody)
  {
    return encode("md5", requestBody);
  }

  private static String encode(String algorithm, String value)
  {
    if (value == null) {
      return null;
    }
    try
    {
      MessageDigest messageDigest = MessageDigest.getInstance(algorithm);
      messageDigest.update(value.getBytes());
      return getFormattedText(messageDigest.digest());
    }
    catch (Exception e)
    {
      throw new RuntimeException(e);
    }
  }

  private static String getFormattedText(byte[] bytes)
  {
    int len = bytes.length;
    StringBuilder buf = new StringBuilder(len * 2);
    for (int j = 0; j < len; j++)
    {
      buf.append(HEX_DIGITS[(bytes[j] >> 4 & 0xF)]);
      buf.append(HEX_DIGITS[(bytes[j] & 0xF)]);
    }
    return buf.toString();
  }

  private static final char[] HEX_DIGITS = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f' };
}
